Magnetic field sensors include a semiconductor chip and a magnet oriented to direct magnetic filed lines through a sensing portion of the chip. Magnetic field sensors are usefully employed as position sensors or rate-of-rotation sensors.
One example of a magnetic field sensor includes a chip sensor attached to a leadframe. The chip sensor is provided to a customer who positions the chip sensor between a permanent magnet and a movable component, such as a gear wheel. It is possible that the customer may bend the leadframe in order to position the chip sensor in a preferred orientation. Apart from the preferred orientation, during use it may nevertheless be difficult to realize perpendicular magnetic field penetration through the chip sensor. Both of the above noted aspects related to the use of conventional magnetic field sensors are undesirable.
Another example of a magnetic field sensor includes a chip sensor package that is positioned relative to a multi-pole magnetic gear wheel. In this case, the gear wheel provides the magnetic field. Such multi-pole magnetic gear wheels are complex and expensive, and the chip sensor package is still subject to the undesirable limitations noted above.
For these and other reasons, there is a need for the present invention.